Welding method and apparatus



Oct.,11, 1938.

P. E. sHAvL-:R 2,132,975

WELDING METHOD AND APPARATUS Filed Feb. 2l, 1935 4 Sheets-Sheet l Oct. 11, 1938.

P. E.. SHAVER WELDING METHOD AND APPARATUS Filed Feb. 2l, 1935 4 Sheets-Sheet 2 HNEHHH Oct. 11, 1938. P El SHAVER 2,132,975

WELDING METHOD AND APPARATUS w/r/vfss.- Per L/ayef @WL-@ Patented Oct. 11, 1938 p UNITED STATES PATENT OFFICE WELDING METHOD AND APPARATUS Application February 21, 1935, Serial No. 7,525

7 Claims.

Considerable dilculty has been heretofore experienced in welding viins or the like upon long tubes such as are used, for example, for heat transfer purposes in stills, condensers or the like. Diiilculties have been encountered particularly Where there are a number of fins to be held in place and welded simultaneously, as, for example, when a tube three inches or four inches in diameter and twenty or more feet long is to have welded to its outside and running lengthwise of it six or eight fins by a continuous weld. Tubes of this type are of such considerable length that they are flexible to an appreciable degree in themselves and, furthermore, are to be associated with ns which are not of great thickness ally more so than the tubes. The operation of holding these fins in proper place against the',

tubes and welding one iin at a time as, for example, by hand welding, is so tedious, timeconsuming, and expensive as to prevent the use of this type of tube wherever possible, although ior certain types of apparatus a tube of such type would be highly desirable.

Furthermore, in the case of a tube of considerable length, the application of heat to one side, as occurs when only one or two welds are made at one time, brings the tube locally to the high welding temperatures, causing such substantial warping as to materially interfere with l proper contact between the two parts to be welded together and to render the tubes useless because of lack of straightness after the welding operation is completed.

Heretofore the only method of welding ns on a long tube has involved carefully clamping the fin against the tube and subsequently using a hand welding apparatus to feed an electrode into and along the line of Contact of the n with the tube. In general, it has been necessary to attach the n tothe tube locally by means of welds of short extent. .In any such case, not only does there occur the warping referred to above, but where the addition of a number of rinato each tube is necessary, the welding apparatus must be run the complete length of the tube for the fixation of each one. The operationl has accordingly been very time-consumv ing' and expensive and the results far from satisfactory.

It is the object of the present invention to provide for holding parts to be welded and the electric welding of elongated tubes or the like in such fashion as to prevent substantial warping or bending during the welding operation, and permit, for example, the holding of fins 4to a tube and a number of lines of welding to be produced simultaneously. The operation, furthermore, can be made automatic and is of this nature in the preferred embodiment of the invention, the tube or other elongated article being moved vertically past electrodes fed at a fixed point. The method and apparatus forming the subject matter of this invention are further adapted to facilitate the handling of long pipes or the like, which has heretofore been dilcult during welding operations.

While the invention is applicable particularly to securing fins or strips of various shapes upon elongated tubes of circular or other cross-section, or elongated members of various shapes, the method and apparatus are also applicable to the closure of seams, particularly where there are a number of lengthwise extending seams to be closed simultaneously. This, together with other useful features of theA apparatus, will be brought out more fully in the following description when read in conjunction with the accompanying drawings, in which Fig. 1 is a diagrammatic sectional view illustrating the association of parts designed for 4automatically carrying out the'method;

Fig. 2 is a plan `view showing a'plurality of associated welding heads arranged to simultaneously produce eight welds in the attachment of eight uns;

Fig. 3 is a detail View showing pneumatically operated means for holding ns and a tube in proper assembled relationship;

The particular apparatus shown hereinlisadapted to handle tubes having a length of twenty feet or more with diameters of three to four inches to which are to be attached eight fins runningsubstantially the full length of the tubes. The apparatus for-handling such tubes is illustrated because tubes of such lengths carrying such a number of fins present major diiculties in handling not only due to their size alone but their flexibility and the difficulty of spacing, holding and welding such a plurality of fins simultaneously.

The working oor or platform 2 supports a stand Il on which the welding elements and other mechanism are mounted. The stand or platform table i is provided with an opening t extending inwardly to its center, which is provided with a circular opening as shown in Fig. 2. The floor 2 is also provided with a laterally extending opening in order that the tubes may be presented to the apparatus from the side, the tubes being originally on a floor below the platform 2. A socket member It is provided initially located adjacent the lower oor t by which the various parts to be assembled and welded may be at least initially supported, although preferablythey are also supported by this socket during the welding operation. As illustrated in Fig. 7, member I carries'a socket II so shaped as to receive the fins to be attached vto the tube and the tube itself, the tube being additionally supported upon an upright post I3, which serves for its guidance. The particular socket used depends upon the individual work which is being done, sockets of special shapes being provided for each job. Instead of separate sockets, of course, adjustable lower holding means may be provided to takercare of Various types of Work. In the -present case, the tube A is designed to have secured to it a plurality of ilns B of various shapes, as indicated in Fig. 3.

Located at suitable intervals between the sock-A et member I0 and the position of the welding electrodes are suitable holding means designed to maintain the parts to be welded together in proper assembled relationship. These are illustrated as comprising curved tubes i2 and I2' carrying inwardly directed pistons I4. In the present case two of these holding means are ily lustrated' which are identical except for the fact that the pistons I4 ln one case extend horizontally and in the other case at an angle to aiord support directly adjacent the welding electrodes. Details of both of these holding means are illustrated in Figs. 3 and 4.

The tube I2 in each case is provided with a proper equalization of -holding pressure is ap plied about the tube. 'I'he extensions 24 are provided with bifurcated ends 25 supporting pins 29 on which, through the medium of roller bearings 21, there are mounted holding rollers 26 having their peripheries properly shaped to engage the particular fins which are being applied. It will be noted that the bearings liet'wholly within the axial limits of the rollers. -Such. arrangement such spattered metal being produced during the welding operation. Two such roller shapes are indicated in Fig. 3, from which the type of engagement which is secured will be apparent. Springs 28 react between the brackets IB and anges on the piston extensions 2d to normally urge the pistons outwardly to the interior of the tubes or cylinders I2.

ln the present case, these holding means are illustrated as operated byfluid or air pressure. It will be obvious -that in place thereof mechanical means may be provided to secure, for example, by the use of suitable springs or screw arrangements, the application of the desired pressure to the parts being welded. rIhe rollers 26 may engage the ns, or if the fins are not oppositely placed, certain oi the rollers .may be made to engage the tube walls.

A welding head 3@ supported by the platform l is provided for the making of each weld. Eachwelding head may be ci substantially conventional character, the electrical arrangementsof `which are hereafter broughtout more fully. So far as the mechanical features are concerned, it may be stated that the heads are provided with rollers for feeding welding wires 32 from supply reels 33, the wires being fed through elongated guiding tubes 3d to the line where welding is to atake place, for example, where the fins contact with the tube. AProvision is made yin the usual fashion for grounding the tube to provide a return circuit.

ln the preferred embodiment of the invention which is illustrated, two motors are provided, one for securing the slow rise of the work during the progress of the welding operation and the other to secure a rapid movement of the work during lowering and initial adjustment. rnotorsv are indicated at 36 and 96 respectively and are designed to drive, through individualclutches, a suitable reduction gearing indicated at 35 and shaft 31 which, through bevel gearing 38, serves to rotate a vertically extending screw 40. The socket member l0 is provided with a threaded hub 44 engaged on the screw so that as the screw rotates the socket member is moved vertically, being restrained against rotation by the slight engagement of an extension upon a vertically extending rod 46.

The screw 40 has attached to its upper end a reversely threaded screw 42 which may be adjusted relatively to it by a hand ratchet arrangement indicated at 48. 'I'his ratcheting arrangement not only serves to secure a relative ne adjustment of the two screws, but also to lock the two together so that, during normal operation, the socket I0 carried by the lower one moves oppositely to a nut member 50 carried by the upper one. 'I'his nut member 50`is held against rotation by sliding engagement with the rod 46. The.

nut member 50 has secured thereto a cable 54 which passes over a pulley,52,supported either directly by a roof orby a. traveling crane. Such crane isdeslrable if it is necessary to move Vthe work after the welding is completed to a substantial lateral extent toa point of delivery. The cable 54 may be secured tothe top of the work in any suitable fashion, for example, t6 `a member clamped to or secured within the tube A. The nished work is indicated at A' in Fig. 1.

The supply of air or liquid for the operation of the pistons I4 is provided through a tube 55 which communicates through a three-way valve 58 with a pipe 62 connected to branches 64 and 68.

A pipe 60 provides for the exhaust of fluid from the three-way valve when it is desired to release These two,

lll

the holding means from the work. A hand operated valve 66 interposed in the line 84 may be used to control the introduction of iiuid to the upper tube or cylinder l2. Communication to the lower cylinder I2, however, is controlled by a manual or automatically operating valve 10 which is of three-way type and serves to control the delivery of iluid to the cylinder through pipe 14 or its exhaust from the cylinder through pipe 18. Normally when pressure is applied to hold the work, the valve operating handle is in its lower position. An extension 16 on the socket member lll, however, is designed to move the handle 'l2 upwardly as it rises, cutting ofi the supply and exhausting the cylinder l2 so that the pistons i4 and the rollers 26 are withdrawn from the work to enable the socket member to pass.

There is best shown in Fig. 3 the type of work which is accomplished by this apparatus. Each oi the fins B is welded to the tube A as indicated along its entire length, the welding wires being into the junctions as indicated in Fig. 2. .As soon as 'the welding starts after the parts to loe welded are assembled, suiliclent engagement in the nature of a tacking is provided so that as the tube A. is lifted, the fins B will be lifted therewith. While the socket member l may be used initially, therefore, it need not ,necessarily be utilized after the welding begins for the raising ci the tube. It may accordingly be arranged so as to have only a limited movement, although in the particular arrangement illustrated it serves for the support of the tube throughout substantially its entire movement. Its upward rise, of course, ceases as soon as it clears the threads on the screw I0. The rollers 26 are primarily relied upon to maintain the parts in proper alignment.

The welding takes place as slow upward movement of the tube and fins occurs. Due to the fact that the tube is vertically and peripherally guided as it moves, there is no substantial `tendency for the parts to become misaligned by ilexure or warping. Warping is particularly prevented7 when a number of iins or the like are being simultaneously welded to the tube, by reason of the evendistribution of heat about the same. Even, however, if only a. single iin or flange is being attached, the type of support which is used, namely, vertical suspension, prevents a disturbance of the proper relative positions of the elements. The pressure applied by each of the rollers 28 may -be of the order of one hundred pounds. After the welding is completed, the tube may be discharged by the suitable lateral displacement of the cable as the nut 50 is caused to move rapidly upwards by the rapid operation of the motor 86.

In order to-lnsure the production of proper results, it is desirable that an apparatus of this type should be automatic to as great a degree as possible so that if any accident occurs which might result in improper work, the entire operation will be interrupted. If welding by any one of the units should be interrupted, all of the welding should cease. Furthermore, if, for some reason as. for example, an overload, the feed of the Work should slow down, the welding should be interrupted, otherwise welds of improper type would result. In order to provide a substantially complete automatic operation, various electrical elements are provided of the types indicated in Fig. 9, which figure represents a wiring diagram showing not only the major operating elements such as motors and generators, but also various tactor Si is illustrated in the lower portier interlocking control devices to lnsur/e the proper combined operation.

There is indicated at 80 a constant potential generator driven by a motor (not shown) supplied with commercial current. Because of the y necessity for ilexlbility of operation and close control, it is desirable to use direct current for the drive of the parts and consequently' the generator is of a direct current type so arranged as to maintain a substantially constant line potential of about sixty volts irrespective ci variations in the commercial supply. llce'constant potential leads from generator are indicated at 82 and 8B.

The armature of the hoist motor 36 is indicated by that numeral in Fig. and is connected across the line through a reversing switch 2id and a relay switch 88, there being in the circuit overload relay coil 85 adapted to open coute 3 @l if an excessive current is taken by the met "Fh l@ o@ n lf3 diagram in its relationship to otite control devices. The motor 3E is provided llelcl 8|! in series with which there a rheostat 552 which is adjustable to speed of operation or. the hoist rheostat may be short-circuited by 'the contact @d in order to secure e. larger starting torque. This contacter Sli will erred to Since the high speed ais; motor' not intereonnected with the automatic controls, it shown in the wiring This motor may be of any desired type operated either the constant potential supply or directly 1. the commercial supply the plant. 3f

The armature of the welding generator is cated at |22. This generator is driven by a motor which may be energized either from the constant potential supply or the commercial supply. A separate exciter (not shown) supplies the shunt field ||8 of the welding generator which has a series field l24. Welding current is supplied through this series field, a reactor 26, contacter |28 and relay coil |38 to the line 82 and to the welding line |32 connected to the electrode i258, which is adapted to weld the grounded work i3d. A separate generator is supplied for each electrode and in the present instance the connections are diagrammatically illustrated in such fashion as to cause the Welder to be of the constant current automatic type. This type of Welder is well known and involves the automatic feed of the electrode wire in such fashion as to maintain a certain predetermined arc. Only so much of the control devices is illustrated as serves to indicate the relationship thereto of certain control relays referred to hereafter. The control devices include a motor H0 provided with a shunt iield ||2 directly connected across the constant potential line, said motor driving a control generator |88 vwhich is connected through a relay control contactor |40 and reversing switch |42 to the armature IM of an electrode feed motor which is provided with a shunt field |46. The fields |48 and |52 are interconnected to the constant potential lines 82 and 84 and to the welding current line |82 through an adjustable potentlometer I 48 and relay control contactors |58 and |84 as illustrated. Switch |42 may be manually operated to eli'ect forward or reverse feed of thwelding wire. The control is otherwise automatic and of conventional type to insure a proper feed during the' operation. The contactors |40, |88 and |84 are controlled as described belor.y

The lower portion of Fig. 9 illustrates the autoi arenoso of the parts when a plurality ci welding heads are associated as in the present case, the parte a sociated with one welding head are shown in full lines, while certain parts associated with a second welding head are shown. in dotted lines, designated by numerals corresponding with those of elements of the rst head, primed. From this arrangement, showing the association of parts for two heads, it will be obvious how duplication can be continued to the extent ci taking care ci any number of heads.

Each of the welding heads has its individual start switch it and stop switch il@ interconnected as diagrammaticaliy illustrated so that when the start switch is closed the stop switch is opened. if only some of the total number oi welding heads are to be operated, then the apparatus is prepared by closing the switches it@ of those heads which are to be operated and leaving switches ldd open (and consequently llt closed) ci those heads which are not to be used, It will` be noted that the various switches lill are shunted across corresponding relay controlled contactors 2115. As will be clear hereafter, the various contactors 2i@ for the several units are arranged in series to close a circuit only if all of contactors di@ are closed or, alternatively, if for each contactor 2l@ that is not closed there is closed the corresponding switch il@ to complete the series.

Two interconnected switches l5@ and 55d, which may be designated as inch and run switches, are provided, there being a single pair of these for the entire apparatus. During normal operation the run switch ld is closed. The purpose of the inch switch will be referred to hereafter.

A master stop switch it and start switch l5@ are provided, the former serving to shut down the entire apparatus and the latter, by its depression, serving to set into operation the various controls to bring the Various parts into action in proper sequence. y

The construction of the control circuit will be clear from a description of the operation involved in starting up the apparatus. Assuming that everything is shut down, the proper switches ltd are closed to predetermine the welding heads which are to be put in operation. As pointed out above, for any switch |68 that is opened, the corresponding switch llt is closed. The operation of the entire apparatus is then initiated by closing the master start switch i513 and holding such switch closed until all of the arcs are struck.

Closure of l5@ energizes relay coil ltd, closing contactor itt. The closing of contactor ltd serves to connect the junction 220 to the line t2.,

this junction being used as a convenient reference point in the further description of the operation.

The energization of 22@ serves, through each of the closed switches E68, to energize a corresponding relay coil W2 of which there is one for each welding head. These relay coils, together with il@ and llt, are not shown duplicated, since the connections of the individual sets will be readily understood. Energizatlon of coil H2 serves to close contactors lll@ and llt. The former of these closes the circuit between the control generator i136 and wire feeding motor ldd. Closure of contactor l'll energizes relay coils il@ and lit. The former closes the contactors l5@ and 55d, energizing the elds ldd'and i552 of the motor lill? and generator 33, respectively, thereby causing the generator to operate the motor to feed the wire forwardly toward the work. The closure of contactors t28 closes the corresponding welding circuit so that when the wire electrode contacts with the work an arc will be struck. As the individual arcs are struck, the corresponding relay coils it@ are energized, closing the contactors 2 l@ and opening the contacts l. As each contactor 2t@ is closed, the corresponding relay coil 2id is energized, closing its associated contactor Zit. When all ci the contactors 2id corresponding to the welding heads which are in operation are closed, they, together with the closed switches il@ of the idle heads, complete a circuit from the junction 22@ through normally closed switches H32 and H58 through relay coil ld@ to line 86. The coil itt is thus energized, closing contactors it@ and itt. The coils itl shunted by resistances itt are adapted to produce a time delay action in the control of contactors 2 l 6 in order that fluctuations of short period or normal instability of the arcs will not result in shutting down the apparatus, contactors 2 it remaining closed through such transient disturbances. The resistances 226 which are shunted across coils 2id whenever the relay coils it@ are deenergized, also serve to aid in such stabilization.

The closure of contactor itt does not immediately effect any result, since its circuit is open at contactor 2id. Closure of contactor E815, however, through normally closed overload relay contactor 9i, connects junction 222 to line 82. Such connection through normally closed contactor lill energizes relay coil 38, which opens contactor is@ and closes contactor H92. Closure of E92 in turn energizes relay coil ist, resulting in closure of contactors it@ and |198. Closure of 98 serves to energize the time delay coils 2M and 262, which serve to thereafter prevent rapid dropping oi the contactors controlled by coils i88 and ist. The time delay is adjustable through the resistance means indicated at 2M, connected across the coils it@ and 2t?. Closure of contactor ist simultaneously with ldd serves to energize both coils 2% and 20d. Energization of coil 2% closes contactor 9d, short-circuiting the leld rheostat 92 for the purpose indicated above of insuring high starting torque of the welding hoist motor 36.

Energlzation of coil 268 closes contactors 2l@ and 2id and opens contactor itl. Closure of contactor 2id connects 'coil 20d between junction 222 and line '8d and consequently this relay is self-holding. The opening of contactor itl deenergizes coil itt and consequently, due to the time delay action, contactor it@ is closed and B92 opened after a predetermined interval. The closure of itil results in energization of coil 2li through now closed contactor 2id. Consequently, contactor t8 is closed and the welding hoist motor started, the torque being initially quite large due to the continued closure of contactor 9d. The opening of H92 results in deenergization of coil llll. Accordingly, after a predetermined interval, contactors ist `and ist are opened, resulting in deenergization of .coil 296, which drops contactor Qt, thus bringing into the shunt field circuit of the welding hoist motor the adjustable rheostat 92. The motor then operates at its predetermined speed to move the work properly past the welding electrodes. Finally, coils lil,

28 and 212 remain energized.

The closure of contactor 2M now connects junction 221| to line 82 through the contaetor |86. Since energization of 220 now results in continued energization of relay |30, this relaybecomes self-holding and the master start switch l54 may be released to its normal opened position. Its opening deenergizes relay |64, which drops contacter |66.

The apparatus vis now in its normal running condition, the work being moved upwardly by the welding hoist motor and the arcs being maintained in proper condition automatically.

The stopping of the apparatus either automatically diie 'to manual intervention is dependent upon rgization coil itil. if the master stop solo d2 is opened, it will be obvioits` that auch deericigsation will result causing contactera let and im' be dropped so that the coil will ierglzed upon release of stop switch ,y opening of switch. it, causing a of 203 and consequently of xeenergoation ot inaction itil re-1 salts lo sperling of. the relays 'which control the weldlrlf rater circuit and also the wire iceding apparatus. Stepping might also occor due overload of the welding hoist motor, which will contacter to be opened, thus aleenergirio relay d and opening the circuit, deenerg.I relay lil@ loyk causing ari opening ci contacter The apparatus will accordingly again down.

Glosl down ol the apparatus also results i from dropping orally one of the contactera 216 diie to more than momentary breaking of the are or e. short circuit of the welding generator resulting from freezing of the electrode to the work. lo the latter case the voltage of the weldgn crater" drops oif, dcenergizing a relay |30 to such extent as to cause it to drop contact 219 just as it will if an arc should become broken. When contact 219 is dropped, the circuit or coil ii is again immediately closed through the Variable resistance 22d and contacter Ztl. The action el coll 2|8 is thus made sluggish and pre-s vents immediate dropping of the contacter 2|6. The interval before the dropping of the last named contacter also to some extent coritrolled by adjustment o resistance |83. Although contacter Mil opens before 22| closes, the operation. is very fast and takes place before the coil M8 is entirely deenergized.

After the apparatus is closed down for any of the above reasons, it must be restarted in the -manner described by pushing the master control button |54 so that the parts oi' the apparatus are brought into operation in proper sequence.

It is sometimes desired to produce welding at only one spot for the purpose of tacking or the like. To eilect such result, it is only necessary to push down the inch button |56 after there has been closed one or more of switches |68 corresponding to the head or heads which are to be operated.

While the inch switch is in parallel with the master starting switch 154, it will be noted that the switch |58 is opened, thereby resulting in operation only so long as the "inch button is held depressed against the action of a spring normally tending to open it and close the run switch |58. Because of the fact that run switch |58 is opened, the coil |80 is not energized and therefore the welding hoist motor is not operated. However, connection is made through one or more of the closed switches |68 through the corresponding relay or relays |12 serving to set into complete operation the associated welding heads in the fashion outlined alcove. It will be obvious that taclring or the like can be accomplished.

It is also sometimes desirable, particularly initially locating the work preparatory to starting the welding, to cause the slowly operating hoist motor rather than the high speed hoist motor to more the work without, however, irl-a ltlatirig action of the Welling heads. La order to accomplish this, there is provided the switch 22d. which is normally operi and may be opened after closure 'oy depression or a button 225 connected thereto. Closure of switch 221i results in einerN gization of the junction l22, which, due to the opera'orls described above, results in the startm or tire welding hoist motor 3E, the 'being under substantial torque by reason of 'the 'ritial short circuiting ci the rheostat 92, whi i series with the shunt field 9G by contacter Si.

the Various automatic electrical l ltioried alcove, provision is made 2d so ers is effected bi" @triatlon oi the main valve it to a source or' compressed fluio. Their with drawal is effected by connecting th cylinders to the atmosphere through passage y arl-other ,manipulation or" the valve 58. The lower old-ing members, however, can be withdrawn for the reason just indicated by movement ol the valve handle l2 by the contact with it of the extension l carried by the supporting member it, such contact serving to move the handle 'il to its upper position to vent the cylinder i2 to the atirl-os-s that it does share the siii-poli ol the work. ln the preliminary ajustements, replay also be used operation oi the wel i heist motor independently ci tlieweldipg means manipulation or" switch ttl. ln the placing of the work and the removal from the apparatus after welding has been completed, the high speed reversible motor 9B is, of course, used.

-As pointed out above, the method and appam ratos of this invention are applicable to perform the welding operations to produce dihererit types oi elongated tubes. In Fig. 5, for example, there is shown a built-up tube of polygonal cross-section made from angle members G welded tow gether at opposite corners as indicated at H. The angle members G may be held together by sultable forms of rollers 26 and welding accomplished simultaneously along the two seams I-I by the use of two heads. At the same time, or thereafter, there may also be attached iins such as indicated at I. Fig. 6 is also illustrative of the character of work which may be accomplished. Scams D may be Welded to hold together the -two semicircular parts C to form a iinished circular tube.

` Such operation may be accomplished particularly where the resulting tube is not to be perfectly rcular'in form but is to have an irregular shape 'cy connecting which, in certain instances, may not loe capable or being rolled, Yout which may he built up by welding together separate parts. Various types ci fins or lengthwise runntng plates or the like may te attachee as indicated at and Ir, and

such attachments may "oe accomplished simultaneously with 'welding of the parts of the tube. To handle parts oi diierent forros of the types iruiicatecir it is only necessary to modify the holding means in a suitable fashion which will loe olovious.

't vwill loe clear that various changes may be made in the emeodimentoi the invention without departing from the scope thereof as donned the following claims,

What L claim and desire to protect 'foy Lett-ers Patent is:

il Welding means including Welding apparatus occupying a substantially fixed position, means for supporting elongated articles and moving there in the direction oi their lengths at a predetermined speed past said welding apparatus to produce progressive welding, aud means :tor in= terrupting the welding if movement does not occur.

2- Welding means including Welding apparat ccupying a substantially xed position, means ier supporting elongated articles and moving them in the direction oi their lengths past said welding apparatus to produce progressive Welding, and means including members occupying fixed positions pressing said articles together to hold them in proper assembled relationship to the said last means, and means for automatically withdrawing said pressing members after a predetermined advance of said elongated articles.

3. The method of welding vertically arranged elongated articles comprising suspending said articles yity their upper ends and moving them vertically in the direction of their lengths past used Welding apparatus, said advance'loeing at the predetermined aisaere portions of said articles which are to loe Weide@ l 5. Welding means including welding apparatus occupying a substantially :ixed position, roe-aus for suspending vertically arranged elongated articles loy their upper ends and for moving them vertically iu. the direction ci their lengths past said Welding apparatus to produce progressive welding, and means operative at a location adjacent the Welding apparatus for pressing said articles together to hold them proper asseniu bled relationship as they move vertically during the Welding operation.

o. Welding means including a plurality o sul:`=1 stantially fixed electrical Welding units, means for suspending vertically arranged elongated articles by their upper ends and forA moving them vertically in thedirection of their lengths past said Welding units to produce simultaneous progressive welds Toy said units, and means for hold- `ing in' proper contact portions of said articles which are to be welded.

' 7. Welding means including a plurality of elecu trical Welding units occupying a substantially fixed position, means for supporting elongated articles and. moving them in the direction oi their lengths past said Welding apparatus to produce progressive Welding, means for predetermlnlng the Welding units, less than all thereof, `which are to operate, and means for substantially simultaneously initiating operation oi' such predetermined units.

i PERRY E. SHAVER. 

